This invention relates to a circular saw, and particularly relates lo a circular saw which includes facility for alignment of a saw blade thereof during the cutting of a workpiece, and for managing the disbursement of chips of the workpiece resulting from the cutting of the workpiece upon use of the saw.
A circular saw includes a generally circular saw blade having cutting teeth or tips located radially about the periphery of the blade. The blade is mounted on a housing of the saw and is rotatably driven during the cutting of a workpiece, under the control of a user or operator of the circular saw. The circular saw also typically includes an upper guard which is fixedly located about an upper portion of the blade to preclude contact with the upper portion of the blade by anyone who is handling or using the saw to form kerfs in the workpiece. In some instances, a lower guard is located about a lower portion of the blade and precludes contact, by a handler or operator, with the blade when the blade is at rest or is being rotated but not placed in a position to form a kerf in the workpiece. The lower guard is mounted to the housing for rotary, or swinging, movement when the saw is manipulated to move the rotating blade into cutting engagement with the workpiece.
In some instances, a flat plate is attached to the housing of the circular saw and is formed with an opening therethrough. The blade is mounted to then housing in such a manner that a first portion of the blade extends outward from the opening and a first major side of the plate, and a second portion of the blade extends from the opening and a second major side of the plate. The flat plate provides a guiding surface which the operator of the saw can position on the workpiece to facilitate control of the circular saw during a cutting operation.
When the circular saw is used to form a kerf in the workpiece, the portions of the workpiece, which are being removed by the rotating blade, separate from the workpiece in the form of chips. The resulting chips are dispersed from the blade-cutting area, and scatter in random directions.
When the workpiece is composed of wood, the chips are heated to some extent as a natural result of the chips being separated from the workpiece by the blade. However, as the chips are being dispersed from the cutting area, the heat thereof is quickly dissipated, and any dispersed chips which may eventually strike an exposed skin area of the operator, or others nearby, are usually cooled sufficiently to be harmless, provided the operator and others nearby are wearing safety glasses. If the workpiece is composed of metal, the dispersed metal chips tend to retain the heat developed during the formation of the kerf. As the heated metal chips are randomly dispersed, many of the chips will strike the operator and could injure exposed skin areas of the operator.
Thus, there is a need for a circular saw which will effectively manage the dispersement of chips, particularly when the saw is used to cut metal, to insure that the chips are discharged in a direction which avoids contact with the operator.
Prior to using a saw to form a kerf in the workpiece, the operator may place guide lines on a surface of the workpiece which define the location of the kerf to be formed. The operator then moves the blade along the guide lines when using the circular saw to form the kerf. In a circular saw which includes the flat plate, the plate may cover all or a portion of the guide lines and thereby obstruct the view of the operator. Circular saws have been designed with a notch or second opening formed in the flat plate, forward of the blade, to provide some opportunity for the operator to see the guide lines during the cutting operation. For example, U.S. Pat. No. 4,856,394, which issued on Aug. 15, 1989, shows a circular saw having a notch formed in a forward edge of a shoe thereof, while U.S. Pat. No. 4,555,849, which issued on Dec. 3, 1985, shows a circular saw formed with a perforation through a forward portion of a flat plate.
While the notch or perforation noted above provide some opportunity for the operator to see guide marks on the workpiece during a kerf-forming operation, a major portion of the guide marks remain obstructed during the operation.
Thus, there is a need for a circular saw with a facility for providing effective kerf-forming guidance for an operator of the saw which includes a shoe with portions extending forward of the blade thereof.
It is, therefore, an object of this invention to provide a circular saw which will effectively manage the dispersement of chips, to insure that the chips are discharged from the circular in a direction which avoids contact with the operator of the saw.
Another object of this invention is to provide a circular saw with a facility for providing effective kerf-forming guidance for the operator of the saw, which includes a shoe with portions extending forward of the blade thereof.
With these and other objects in mind, this invention contemplates a circular saw which includes a housing, a mount for receiving and supporting a saw blade in a given plane, and a motor located within the housing and coupled to the mount for driving the mount and, thereby, the saw blade to be mounted thereon. A shoe is attached to the housing and is formed with an opening therethrough which is located in the given plane. The opening is formed with a first section of a first prescribed width about the given plane and with a second section of a second prescribed width about the given plane, where the second prescribed width is greater than the first prescribed width.
This invention further contemplates a circular saw which includes a housing, a mount for receiving and supporting a saw blade in a given plane, and a motor located within the housing and coupled to the mount for driving the mount and, thereby, the saw blade to be mounted thereon. A shoe is attached to the housing and a stripe is located on one side of the shoe which is visible to an operator when using the saw, and is aligned with a forwardmost cutting location of the blade The stripe extends at an angle with respect to the given plane of the blade.
Additionally, this invention contemplates a circular saw which includes a housing, a mount for receiving and supporting a saw blade in a given plane, and a motor located within the housing and coupled to the mount for driving the mount and, thereby, the saw blade to be mounted thereon. A shoe is attached to the housing. A guard is attached to the housing and extends outward from the one side of the shoe. The guard forms a substantially enclosed chamber about an area in which cutting portions of the blade are to be moved during cutting of a workpiece. The guard is formed with a first end edge at one end thereof in a forward area of the saw where the blade is to cut into the workpiece, and a second end edge at a second end of the guard spaced from the first end edge in a rear area of the saw. The first end edge of the guard is located in juxtaposition with the one side of the shoe and sufficiently close to the shoe to essentially preclude the discharge of chips through any space between the first end edge and the shoe in the forward area. The second end edge of the guard is adjacent the one side of the shoe to define an opening therebetween which is of sufficient size to allow chips to be discharged therethrough but to control the direction of movement of the discharged chips away from the saw.
Further, this invention contemplates a circular saw wherein the guard is formed with an inner edge portion, which is contiguous with the first end edge of the guard, in a direction away from the shoe. A wing wall is formed on the guard and extends from the inner edge portion of the guard toward the given plane.
Also, this invention contemplates a circular saw which includes a first guard which forms a substantially enclosed chamber radially outboard of an area in which cutting portions of a circular blade of the saw are to be located and moved during cutting of a workpiece. A second guard is mounted for movement into a first path within the enclosed chamber, where the first path is radially outboard of the area in which the cutting portions of the blade are to be located. The enclosed chamber is formed with a second path which is radially outboard of the first path thereof to facilitate the managed disbursement of chips therethrough.
Other objects, feastures and advantages of the present invention will become more fully apparent from the following detailed description of the preferred embodiment, the appended claims and the accompanying drawings.